package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    //导入锁
    @Resource
    private RedissonClient redissonClient;
    //初始化proxy
    private IVoucherOrderService proxy;

    //加载脚本
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    //脚本初始化
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }



    //创建线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    //初始化完毕就会执行此方法
    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    /**
     * 使用消息队列操作数据库，优化应用
     */
    private class VoucherOrderHandler implements Runnable{
        String queueName="stream.orders";
        @Override
        public void run() {
            //不断从队列取值
            while (true){
                try {
                    //1.获取消息队列中的订单信息,没有元素卡在这XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS streams.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //2.判断消息是否成功
                    if (list == null || list.isEmpty()){
                        //2.1.如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    //2.2.如果获取成功，可以下单
                    //3.解析列表中的订单
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3.创建订单
                    handleVoucherOrder(voucherOrder);
                    //4.ACK确认SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    handlePendingList();
                }
            }
        }
        /**
         * 处理没有获取成功的异常
         */
        private void handlePendingList() {
            //不断从队列取值
            while (true){
                try {
                    //1.获取pending-list中的订单信息,没有元素卡在这XREADGROUP GROUP g1 c1 COUNT 1 STREAMS streams.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //2.判断消息是否成功
                    if (list == null || list.isEmpty()){
                        //2.1.如果获取失败，说明pending-list没有异常消息，结束循环
                        break;
                    }
                    //2.2.如果获取成功，可以下单
                    //3.解析列表中的订单
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    //3.创建订单
                    handleVoucherOrder(voucherOrder);
                    //4.ACK确认SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常",e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        throw new RuntimeException(ex);
                    }
                }
            }
        }
    }



    //不再使用阻塞队列，使用stream消息队列
/*    //创建阻塞队列
    private BlockingQueue<VoucherOrder> orderTasks =new ArrayBlockingQueue<>(1024*1024);
    private class VoucherOrderHandler implements Runnable{

        @Override
        public void run() {
       //不断从队列取值
       while (true){
            try {
                //1.获取队列中的订单信息,没有元素卡在这
                VoucherOrder voucherOrder = orderTasks.take();
                //2.创建订单
                handleVoucherOrder(voucherOrder);
            } catch (InterruptedException e) {
                log.error("处理订单异常",e);
                Thread.currentThread().interrupt();
            }
       }
        }
    }*/

    //让从线程去处理数据库的读写
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        //获取用户id
        Long userId = voucherOrder.getUserId();
        //创建锁对象
       // SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        //通过redisson创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);

        //尝试获取锁
        boolean isLock = lock.tryLock();
        //判断释放获取锁成功
        if (!isLock){
            //获取锁失败，返回错误或重试
            log.error("不允许重复下单");
            return;
        }try {
            proxy.createVoucherOrder(voucherOrder);
        }finally {
            //释放锁
            lock.unlock();
        }

    }


//    private IVoucherOrderService proxy;
    /**
     * 抢优惠价通过redis优化
     * @param voucherId
     * @return
     */
   /** @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户id
        Long userId = UserHolder.getUser().getId();
     //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );
        int r=result.intValue();
        //2.判断结果为0
        if (r==3){

            //2.1为3，库存不足
            return Result.fail("优惠劵不存在");
        }
        if (r!=0){
            //2.1不为0，库存不足或者不能重复下单
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //2.2为0，有购买资格，把下单消息保存到阻塞队列
        //2.3.创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        //2.4订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        //2.5用户id
        voucherOrder.setUserId(userId);
        //2.6代金卷id
        voucherOrder.setVoucherId(voucherId);
        //2.7放入阻塞队列
        orderTasks.add(voucherOrder);

        //3.获取代理对象（事务）
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        //4.返回订单id
        return Result.ok(orderId);
    }

*/


    /**
     * 抢优惠价通过redis优化-消息队列
     * @param voucherId
     * @return
     */
    @Override
   public Result seckillVoucher(Long voucherId) {
       //获取用户id
       Long userId = UserHolder.getUser().getId();
       //获取订单id
        long orderId = redisIdWorker.nextId("order");
       //1.执行lua脚本
       Long result = stringRedisTemplate.execute(
               SECKILL_SCRIPT,
               Collections.emptyList(),
               voucherId.toString(), userId.toString(),String.valueOf(orderId)
       );
       int r=result.intValue();
       //2.判断结果为0
       if (r!=0){
           //2.1不为0，库存不足或者不能重复下单
           return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
       }

       //lua脚本已经完成
/*       //2.2为0，有购买资格，把下单消息保存到阻塞队列
       //2.3.创建订单
       VoucherOrder voucherOrder = new VoucherOrder();
       //2.4订单id
       voucherOrder.setId(orderId);
       //2.5用户id
       voucherOrder.setUserId(userId);
       //2.6代金卷id
       voucherOrder.setVoucherId(voucherId);
       //2.7放入阻塞队列
       orderTasks.add(voucherOrder);*/

       //3.获取代理对象（事务）
       proxy = (IVoucherOrderService) AopContext.currentProxy();

       //4.返回订单id
       return Result.ok(orderId);
   }





    /**
     * 抢优惠价
     *
     * @param voucherOrder
     */
/*    @Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询优惠价
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //2.判断秒杀是否开始
        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
            return Result.fail("秒杀尚未开始");
        }
        //3.判断秒杀是否结束
        if(voucher.getEndTime().isBefore(LocalDateTime.now())){
            return Result.fail("秒杀已经结束");
        }
        //4.判断库存是否充足
        if(voucher.getStock() < 1){
            return Result.fail("库存不足");
        }
        //获取用户id
        Long userId = UserHolder.getUser().getId();
        //synchronized加入悲观锁,通过用户id给同一个用户加锁,每掉一次tostring对象，地址值都会变，使用intern可以比较数值
        //直接使用createVoucherOrder等于this.createVoucherOrder会导致事务失效
        //使用代理对象的createVoucherOrder--要导入依赖：
//                <dependency>
//            <groupId>org.aspectj</groupId>
//            <artifactId>aspectjweaver</artifactId>
//        </dependency>
//        和在启动类添加注解
//        @EnableAspectJAutoProxy(exposeProxy = true)


//        synchronized (userId.toString().intern()) {
//            //获取代理对象（事务）
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        }

        //基于redis的分布式锁
        //创建锁对象
       // SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        //通过redisson创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);

        //尝试获取锁
        boolean isLock = lock.tryLock();
        //判断释放获取锁成功
        if (!isLock){
            //获取锁失败，返回错误或重试
            return Result.fail("不允许重复下单");
        }try {
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        }finally {
            //释放锁
            lock.unlock();
        }
    }*/

    //synchronized加入悲观锁,通过用户id给同一个用户加锁
    //改造版,在数据库中创建订单
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //5.一人一单
        Long userId = voucherOrder.getUserId();
        //synchronized加入悲观锁,通过用户id给同一个用户加锁,每掉一次tostring对象，地址值都会变，使用intern可以比较数值
        //Transactional会导致锁失效，所以加到函数外面
        //synchronized (userId.toString().intern()){
            //5.1.查询订单
            Integer count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
            //5.2判断是否存在
            if(count > 0){
                log.error("不允许重复下单");
                return;
            }
            //6.扣减库存eq是条件
            boolean success = seckillVoucherService.update().setSql("stock = stock - 1")
                    .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock",0).update();
            if(!success){
                log.error("库存不足");
                return;
            }
            //保存订单
            save(voucherOrder);

        }


    //}
}
